Operating system: Windows 10
Graphics card: NVidia GForce GTX 950
Blender 2.8 e4dbfe0a98c1 2018-12-26
If Live Unwrap is enabled in the "Active Tool And Workspace Settings" tab of the properties editor, whenever I create a new seem the UV Islands are scaled to a big size (several times the size of the UV Grid). The UV is updated as it should be, but instead of reorganizing the islands inside the UV grid square, the islands become huge and get overlapped.
Exact steps for others to reproduce the error
1- Select a geometry;
2- Enter the UV Editing Workspace;
3- Use the Unwrap command;
4- Activate the Live Unwrap option in the mesh options panel of the "Active Tool And Workspace Settings" tab of the properties editor;
5- Create a new seam in the object;
6- See how the islands got huge and overlaped in the uv editor.